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Citrus temperatures

Posted by mksmth oklahoma 7a (My Page) on
Wed, Oct 3, 12 at 17:46

I know this has been talked about a lot and there are many different view points, opinions, and scientific facts spread out through this forum and on the web. But what i would like to hear especially with the winter months approaching is what is your level of concern for cold temps and what temperatures make you nervous.

I for one dont get too worked up until the forecast is for over night lows in the high 30s. For instance we have had lows in the 50s and some upper 40's but our highs for the day have been 70-80 and I have not thought even once about putting stuff in the greenhouse. This weekend we have one day forecasted for a low of 38 and daytime high of 50 then back into the 70's after that. Ill probably do something for that one night but that would be it.

Maybe Im wrong but I think most of us agree that damage really doesnt occur until freezing or below and some times a decent frost. For me I know my trees will slow down at lower temps but cold damage is really my biggest concern.

I say this because I have seen people start to get worried as the temperatures get in the 40's and I just wanted to see if anyone else is as nonchalant about this as I am. As long as the days warm up I have no problem exposing my trees to the 40's. Obviously I would prefer my plants to be at the optimum temperature all the time but I know that while its possible its not always an option.

I dont know maybe Im being dumb but I was just thinking that maybe some people are getting a bit too worried about their trees, not that its a problem but at the same time maybe its unnecessary.

Mike


Follow-Up Postings:

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RE: Citrus temperatures

Mike, you know what?

I am staring to become like you.

I am at the point now that I would rather leave them longer outdoors, than expose them to jail conditions much too early.

yes, mine do slow down too, even get a bit yellow lately, but I can always green them up any time I want because I know that I am control.
So yes, I am getting a bit more brazin while at teh same time less worried.
When temps are in the low 50's here by day, it is always certain that temps will drop 20 degrees by night unless it's cloudy.

So only on those days do I get quite concerned and that is when I bring them all in for the night.

I am starting to think that my trees like to rest during the winter than to be force grown under warm conitions all the time.
I seem to get more profuse flowering and fruits the following spring after they have rested.

So, they are still outside unless I see sure signs of decline or stress.
Then once I bring them in, they go into an unheated roon which also extends their rest and a lack of pest issues.

So no, you are not dumb, but I think you know your trees more than ever before.

Mike:-)


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RE: Citrus temperatures

It depends on sooooo many things. Maybe first is the variety; some are much more tolerant than others.

Second, the empirical number... 28 degrees, 35 degrees, etc. is less important than the environmental issues; is the plant protected, is it next to a warm wall, do you have vegetation under the tree that raises the orchard floor, is the soil wet or dry, what is the dewpoint (a measure of humidity.. a low dewpoint means your plants are more vulnerable)... most of these things are available on your local agricultural radio station daily.


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RE: Citrus temperatures

  • Posted by mksmth oklahoma 7a (My Page) on
    Wed, Oct 3, 12 at 21:11

I agree john. There are so many other factors to consider. I just hope that someone who may be concerned will know that 40 degrees wont damage their trees. Now 40 degrees,rain and no sun for days will probably cause root problems but now we added different variables.

Mike


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RE: Citrus temperatures

Not an expert by any means, but I think the reasoning of cold can be good, for any reason other than the getting the fruit to set may be misplaced.

I have recently cleaned out the local garden center of their clearance motley citrus. As a new parent I have the same concerns. If a plant goes dormant at 40, 50, 60 degrees what is the breakpoint for bringing it in? I suppose 75 degrees and limited light (active and starving)may be worse than 40 and dormant.

I think I need a citrus pedatrician to calm the nervous new parent.

I have found that cold is all too often accompanied by wet and rainy. I've considered putting a rain coat on the pots.


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RE: Citrus temperatures

First and last, there is no dormancy in citrus; it is an evergreen plant, needing the same care and conditions the whole year... What more? If it is a container plant, to be moved in and out, you need to ask the container gurus here.


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RE: Citrus temperatures

Dog

Like john said there is no dormancy. What we do as container growers is balance a fine line between either slowing the trees down and giving them an environment that is conducive to that or giving them an environment that allows the tree to grow normally or as close as possible.

Its been stated quite a bit here and other places that we need to try and maintain a minimum of 55 degrees at the root zone to keep the roots active enough to prevent leaf drop. Leaf drop is not a sign of the tree going dormant but infact usually a sign that there is a problem. Most generally you will get leaf drop when moving the trees indoors and or when they are placed by a good light source but the roots arent active enough to send water to the leaves to allow for transpiration to cool them.

cold and wet is one of the biggest issues with trees that we see here during the next few months. Keep them warm or keep them on the dry side but never cold and wet.

mike


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RE: Citrus temperatures

I worry most when they forecast low 30's with strong winds. My trees are big and I have a lot of them so moving them around to protect them can only be done a few times. I know that there is only so much that one man can do. My schedule tends to get busy in the fall which only adds to the pressure. So I do the best I can and hope everything works out okay. Lucky for me I bought a large hoophouse this fall. It is big enough to shelter the entire collection and allow them to grow even bigger and I will only have to move them if I want to. Unlucky for me - I now have to build the dang thing and get it finished before first frost.

Here's hoping for a late frost!


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RE: Citrus temperatures

  • Posted by mksmth oklahoma 7a (My Page) on
    Thu, Oct 4, 12 at 10:27

Hey Mike

sorry to just now reply to your comments. thank you for them

Your methods of keeping your trees happy is a true testament to your love for them and the results show it.

Im truly amazed at how you and the other northern growers are able to keep your trees looking fantastic all winter.

Mike


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RE: Citrus temperatures

My citrus have come through temps in the mid-20's for several nights with no problems. They're in the ground. Once they get established and are a few feet tall, they're fairly freeze resistant. There are citrus all over my neighborhood that have gone through freezes, uncovered, with no problems. They're too large to cover. If it stays below freezing for weeks or months, though, I don't know what that would do, but short freezes aren't a problem.

When mine were small, I covered them and put lights under the covers at night. But my Meyer lemon didn't have any protection at all when we had temps in the mid-20's at night, and below freezing during the day, for a solid week, two winters in a row. Hope this helps.


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RE: Citrus temperatures

Mike! Thanks pal!

By the way, I love to see how far you have come. Your trees have been looking great these days.

Mine are all still outside and I am still getting new growth, slowed a lot though, even with these crazy temps.
I can tell you I'll be hauling them all into the porch come Sunday nite since they are forcasting our first killing frost.
Then, it seems as if the temps warmn up again shortly after that. I hate kicking myself in the but wishing I had left them out longer after one or two cold days.

I hear ya everyone else.lol What a pain at times, right?

Oh I wish I lived in a zone that does not get a frost until about November.


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RE: Citrus temperatures

So would you recommend bringing them in, and then waiting for a period of time (several days?) before attempting to hit them with a grow light?


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RE: Citrus temperatures

Interesting. 28 degrees to 43 degrees can make citrus plants grow.


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RE: Citrus temperatures

Johnmerr:

You have confused dormant with deciduous.


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RE: Citrus temperatures

Veron, 28 degrees to 43 in containers will eventually KILL your plants.
I woudl bring them inside and keep them out of the cold like that. In fact, your soil will also have an effect on your tree at those temps, and that is another discussion.

Doglips, I love that name by the way.lol

I have never had an issue setting lights on them as soon as they come inside.
The length of time you keep them on in unison with the temps is what is key to good care practice.

Mike


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RE: Citrus temperatures

Tantanman,

Because you are a good friend of Mayan Meyer Lemons for your TX A&M connection, I will choose to ignore the fact that you think my lack of education (UCD)means I don't know the difference/distinction between deciduous and dormant. Maybe it is like the difference between involved and committed; when you have ham and eggs for breakfast, the chicken is involved; but the pig is committed.


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RE: Citrus temperatures

I leave my potted citrus outside all winter here in northern California. My experience with leaf damage based upon temperature is below. Of course, these numbers assume that the plants have acclimated to cooler temperatures and sub-freezing temperatures occur only at night (usually only for a few hours).

≥28 degrees: little to no damage
26-27 degrees: significant damage to new or tender growth only
25 degrees: damage to some outer mature growth (~5-10% of leaves on 3-4 foot tall plants, but inner growth fine)
<25 degrees: unknown

Of course, there is variability in the cold tolerance of different citrus varieties. Limes and lemons are most susceptible, followed by grapefruit then oranges then mandarins. At these temperatures, however, I have only noticed minor differences between the different varieties, mainly between the lemons/limes and others.

-Brett


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RE: Citrus temperatures

Brett.. I am curious...

In what part of California do you live?

I am thinking in a area where you only get a few hours of those temps and then it warms up nicely by day?

Over here, temps are suppose to be in the high 20's by midnight and not warm into the at least low 50's until about well after noon the next day.
Over here, exposed to temps that low for that amount of time would kill mine.
The sun here serves no purpose except to light my way to work and expose the pretty colors on our trees, because even the warmth of it has escaped us unless we get a warm front to come through and warm us into the 60's or better until next spring.

I find that once my trees are expose to even the low 40's for more than a few days here, it takes forever to warm up here, yet again causing my trees to sulk and decline if exposed to temps like that for too long.

I can only think of one place it might work. Resting them up against my south side facing home on the roof to get sun as soon as it rises while it heats the wall behind them.

Here, all the nurseries have pulled theirs in over two weeks ago which tells me something.

Thanks for your finding along with your time. I hope you live in a beautiful place. I have always wanted to visit there. I have a best friend that lives there and I have yet to visit him. Have a great day!

Mike


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RE: Citrus temperatures

48 countries and 46 of the 50 US States; and when anyone asks me "what is your favorite country", I always say California.


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RE: Citrus temperatures

Hi Mike,

I live in Novato which is about 30 minutes north of San Francisco. Our freezing hours tend to be between midnight and 9 a.m. Days in the winter are generally in the 50s, but freezing is rare after 9 in the morning. When it is really cold we can get 6-8 hours of sub-freezing temperature, but this is unusual.

I am originally from the east coat, so I am like a kid in a candy shop while gardening in California. There is so many options where we live. I just hope the citrus greening doesn't get us.

-Brett


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